Letterpress printing ink

ABSTRACT

A non-petroleum base newspaper letterpress printing ink comprising a blend of Gilsonite (uintaite) flakes and tall oil fatty acid together with carbon black pigment. The proportions of the Gilsonite and the tall oil fatty acid may be varied, as viscosity requirements change due to differences in press speeds, newsprint characteristics, and the like. The ink thus has readily adjustable viscosity, together with an enhanced flow and penetration characteristics, while being extremely economical to manufacture.

CROSS-REFERENCES TO RELATED APPLICATIONS

A continuation-in-part of applicant's PRINTING INK, application Ser. No. 337,220, filed Jan. 6, 1982, issued as U.S. Pat. No. 4,419,132 on Dec. 6, 1983. The present application is directed to a range of letterpress printing ink formulations. A copending application Ser. No. 556,471, entitled OFFSET PRINTING INK was filed Nov. 30, 1983.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Printing inks, particularly letterpress newspaper printing inks which have a non-petroleum base, which are environmentally acceptable, while providing reduced misting with extra mileage and good quality.

2. Description of the Prior Art

Discussed in a PRIOR ART STATEMENT being submitted separately.

SUMMARY OF THE INVENTION

According to the present invention, a non-petroleum base letterpress ink is formulated from carbon black pigment and a blend of Gilsonite (uintaite) with tall oil fatty acid. The resultant printing ink provides an ink having enhanced viscosity, flow and penetration characteristics, while being exceptionally economical to manufacture. As a result, the ink is highly suitable for printing at contemporary press speeds, is quick drying and, thus, avoids the conventional problems of "offset" and "strike thru".

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present ink, having a non-petroleum base, is without dependence upon a diminishing petroleum supply, is environmentally acceptable and competitive in cost with the materials used in commercial letterpress and offset inks.

Procedure

70 Parts by weight of FA-1 grade tall oil fatty acids are heated with 30 parts of ZECO 11 A grade Gilsonite from Ziegler Chemical Corporation at 300° F. After solution of the solid Gilsonite, the blend is cooled and filtered. After the blend is made, carbon pigment is dispersed within the blend with a Morehouse Mill. The "Elftex" carbon black pellets were ground to a National Printing Ink Research Institute grindometer reading of one (1). Viscosity adjustment can be made by adding small amounts of tall oil fatty acid as a final step if necessary. This ink had the following physical properties:

EXAMPLE I

A. Formulation of "ANPA-247" Letterpress Ink:

    __________________________________________________________________________                                         PERCENTAGE                                 MATERIAL             SOURCE         by WEIGHT                                  __________________________________________________________________________     ELftex - 8           Cabot Corporation                                                                             10                                         Carbon Black         125 High Street                                                                Boston, MA 02110                                          70/30 FA-1 Gilsonite Arizona Chemical Corporation                                                                  87.8                                       Blend                Wayne, NJ 07670                                           Milori Blue Toner 910B                                                                              Dainichiseika Color &                                                                         2.2                                                             Chemical Company                                                               20 Hook Mountain Road                                                          Pine Brook, NJ 07058                                      TOTAL                               100                                        which breaks down to:                                                                           Carbon 10.0%                                                                   Toner  2.2%                                                                    Gilsonite                                                                             26.3%                                                                   Tall Oil                                                                              61.5%                                                                   Fatty Acid*                                                                    TOTAL  100.0%                                                 __________________________________________________________________________     *FA-1 Tall Oil Fatty Acid, specified as follows:                               Product Characteristics    Specification                                                                         Typical Lot                                  Color, Gardner, 1963        9 max 5                                            Acid Value                 190 min                                                                               194                                          Saponification Value              197                                          Iodine Value                      131                                          Composition:                                                                   Moisture, %                       Less than 0.1                                Ash, %                            Less than 0.001                              Rosin Acids, %              5.0 max                                                                              4.5                                          Unsaponifiables, %          3.0 max                                                                              2.7                                          Fatty Acids Total, %              92.8                                         Fatty Acid Composition:                                                        Linoleic, Non-Conjugated, %       34                                           Linoleic, Conjugated, %           9                                            Oleic, %                          44                                           Saturated, %                      5                                            Other Fatty Acids, %              8                                            Specific Gravity, 25°/25° C.                                                                       0.906                                        Weight Per Gallon, 25° C., Lbs.                                                                           7.53                                         Viscosity, Gardner-Holdt, 25° C.                                                                          A                                            Viscosity, SUS, 100° F.    100                                          Flash Point, Open Cup, °F. 400                                          Fire Point, Open Cup, °F.  440                                          TYPICAL PROPERTIES OF CABOT FURNACE PROCESS                                    CARBON BLACKS FOR PRINTING INK APPLICATIONS                                                                            Oil (DBP)                                                       Surface Area                                                                           Particle                                                                              Absorption                                                                              Tinting                                                                             Volatile                                                                            Fixed                                  Nigrometer                                                                           (N.sub.2 S.A.)                                                                         Size   cc/100 grams                                                                            Strength                                                                            Content                                                                             Carbon              Fluffy Pellets     Index m.sup.2 /gm                                                                            Millimicrons                                                                          Fluffy                                                                             Pellets                                                                             Index                                                                               %    %                   __________________________________________________________________________            ELFTEX ® Pellets                                                                       90    75      27     --  123   99  1.0  92.5                       ELFTEX ® Pellets 115                                                                   90    66      27     --  115  100  1.0  92.5                ELFTEX 8           90    85      27     103 --   100  1.0  99.0                ELFTEX 12          93    45      37      95 --    73  1.0  99.0                __________________________________________________________________________      The above data in no way constitute a specification or certification for       any particular shipment or shipments, but simply represent typical values      based on analyses of spot samples from actual recent production of these       grades.                                                                        MOGUL, BLACK PEARLS, REGAL, ELFTEX, STERLING, and VULCAN are registered        trademarks for carbon blacks manufactured by Cabot Corporation           

B. Physical Properties of ANPA-247--Example I:

    ______________________________________                                         Inkometer Tack (400 RPM)                                                                            2                                                         Viscosity, Brookfield 25° C.                                                                 43.2 Poises                                               NAPIRI Grindometer   0                                                         Flow 45° Inclined Plane                                                                      6 Inches/Minute                                           ______________________________________                                    

C. Environmental Data:

Gilsonite has been the subject of long term animal studies which indicate it is a non-toxic organic substance which is noncarcinogenic. In accordance with Section 710.4 of the Toxic Substances Control Act, Gilsonite, as a naturally occurring mineral, is automatically included in the initial inventory. The Chemical Abstract Registry Number is 12002-43-6.

D. Comparison with Commercial Letterpress Inks:

The Harrisburg Patriot and Evening News showed ANPA-247 ink to print well, to be low-misting, and to have high mileage. Laboratory tests at ANPA/RI for rub off, viscosity and tack, shown in the following table, point out the differences between it and standard letterpress ink, as used at The Patriot and Evening News.

It was noted at The Patriot that the inks were quicker drying than the standard news inks and did not dirty the pipe rollers on the press, as did conventional slow drying inks when high press speeds are used. Rub off of dried inks on the hands and on the other newspapers in a stack is another property which is minimal.

    ______________________________________                                         RUB-OFF, VISCOSITY, TACK OF ANPA-247 - Example I                               (Andersson and Sorenson Rub Tests)                                                                    Brookfield                                                                               Inkometer                                                            Viscosity Tack                                          INK        Rub-off %   Poises    400 R.P.M.                                    ______________________________________                                         ANPA-247   0.52        43.2      2.0                                           Standard Ink                                                                              2.53        31.5      1.75                                          ______________________________________                                    

EXAMPLE II

A. Formulation of ANPA-247B Letterpress Ink:

The foregoing Example I refers to runs on regular letterpress. The 247B ink, which was made to run on an Anilox press, was formulated as follows:

    ______________________________________                                                                        % by                                            MATERIAL       SOURCE          WEIGHT                                          ______________________________________                                         Elftex Pellets 115 Carbon                                                                     Cabot Corporation                                                                              18.1                                            Black Pigment  125 High Street                                                                Boston, MA 02110                                                Gilsonite (Zeco 11A)                                                                          Ziegler Chemical                                                                               16.4                                                           & Mineral Corp.                                                                P.O. Box 455                                                                   Great Neck, NY 11021                                            FA-1 Grade Tall Oil Fatty      65.5                                            Acids                          100.0                                           ______________________________________                                    

These formulations increase mileage of the ink significantly, compared to commercial letterpress ink.

The ANPA-247B blend can also be used for offset inks. An ink with about 20% carbon content and the remainder being the above-described blend, has been printed successfully on a Goss Urbanite offset press.

B. Comparison with Commercially Available Oil Base Inks:

The Easton (PA) Express, when running ANPA-247 non-petroleum ink, had pointed out that the mileage for the ink was very good. By their estimates, it was at least 30% better. Consequently, a sample of their regular production oil base ink was obtained and a comparison was run on the two inks on a Hoe Letterpress.

Each ink was run on about 900 lbs., or one roll of paper, and the amounts of ink were weighed before and after the run to determine the amount consumed. The same plates and impression pressures were used. ANPA-247 produced 35% more pages per pound at a comparable solids print density of 0.98, which is the density used at The Express.

It is apparent from the above formula tabulation that the amount of Gilsonite in the ink may be varied from about 16% to about 25%. If the Gilsonite content is reduced significantly, strike thru and smearing of the newsprint are accentuated. If the Gilsonite content is increased significantly above 25%, viscosity will increase to the extent that poor flow and uneven lay or coverage will result in printed copy. Also, less mileage will ensue, since the amount of pigment will need to be reduced in order to allay the increased viscosity, inasmuch as pigment content increases viscosity. Thus, reduction in pigment content would decrease mileage.

EXAMPLE III

    ______________________________________                                         Carbon black pigment                                                                               17%                                                        Gilsonite (uintaite)                                                                             18.6%                                                        Tall oil fatty acid                                                                              64.4%                                                        ______________________________________                                    

The foregoing example was used at Allentown Call, providing a fluid ink for printing at higher speeds with good results.

In printing with contemporary high speed presses, which may produce 80,000 impressions per hour, one cannot use inks which require oxidation or drying so as to prevent smear. The present ink is adapted to have a special viscosity, enabling it to be absorbable in contemporary newsprint. The Gilsonite ingredient enhances the viscosity, such that there is less penetration into the newsprint fibers while eliminating smearing. The Gilsonite may be obtained commercially at $0.11 per pound. The letterpress ink may be formulated, so as to have a viscosity in the range of 20-500 poises. Operating at press speeds of 50,000 impressions per hour, it was found that the ink having a viscosity of 90 poises did not dry fast enough. Ink viscosity of approximately 35 poises was approximately correct. In addition, the "flow" characteristics of the ink, that is, the ability to flow over the plate surfaces while covering the dots on the plate, is a critical parameter. It is found that at a plate temperature of 25° C. (77° F.), enough Gilsonite must be employed to retard the flow within a sufficient range.

Flow characteristics and viscosities of various ink formulations have been determined, as follows:

    ______________________________________                                         Formulation %                                                                  ______________________________________                                                    FLOW IN INCHES 25° C. (77° F.)                                     Ink 287B  283    247-1                                                                               276   293                                   ______________________________________                                         FA-1         66.2      64.14  56.4 66.1  70.1                                  Carbon        9.5      17.02  19.8 16.2  12.3                                  ZECO 11A     24.3      18.54  23.8 17.7  17.6                                  ______________________________________                                         TIME, MINUTES                                                                               Ink 287B  283    247-1                                                                               276                                         ______________________________________                                         1            61/8      3      11/8 33/8   91/4                                 2            81/4       41/8  17/8 43/4  121/4                                 3            93/4      5      23/8 53/4  143/4                                 ______________________________________                                    

BROOKFIELD VISCOSITY

The lower limit of viscosity and upper limit of flow has not been determined to date. The ink appears to have less strike-through even at low viscosities and a long flow length versus petroleum inks.

Principal advantages of the ink include the capability of printing at high press speeds, the low cost of formulation and the elimination of petroleum. The ingredient, Gilsonite, may be fed to animals and indeed, fatty acids are edible.

It is found that letterpress and offset inks having a viscosity in the range 20-over 1000 poises may be suitable. The over 1000 poises ink would be the upper limit when the inking cylinder actually contacts a reservoir of ink. Ink of such viscosity would be difficult to pump in some modern press usage. The ink viscosity is related, of course, to the density of the newspaper stock and the thickness of the page, as well as press speed.

A low viscosity letterpress and flexographic ink formulated for fast drying and decreased set-off onto other sheets of paper in the folded newapaper is:

EXAMPLE IV

    ______________________________________                                         Carbon black pigment                                                                             12.3%                                                        Gilsonite (uintaite)                                                                             17.6%                                                        Tall oil fatty acid                                                                              70.1%                                                                           100%                                                        ______________________________________                                    

EXAMPLE V

    ______________________________________                                         Material           Percentage                                                  ______________________________________                                         70/30 Fatty Acid/Gilsonite                                                                        75.3                                                        Carbon Black (115 Pellets)                                                                        6.1                                                         Toner              0.8                                                         FA-1 Fatty Acid    17.8                                                        ______________________________________                                    

Manifestly, various proportions of the Gilsonite and tall oil fatty ingredients may be employed without departing from the spirit of invention. 

I claim:
 1. A letterpress printing ink composition consisting essentially of:a. Carbon black pigment in the range 6.0 to 19.8% b. Gilsonite in the range 16.4 to 26.3%, and c. Tall oil fatty acid in the range 52.7 to 70.5%.
 2. A letterpress printing ink composition as in claim 1, wherein said Gilsonite and tall oil fatty acids are blended by heating at approximately 300° F. prior to cooling, filtering and dispersing with carbon black pigment.
 3. A letterpress printing ink composition consisting essentially of:a. Carbon black pigment 10% b. Gilsonite 26.3% c. Tall oil fatty acid 61.5%, and d. Black toner 2.2%.
 4. A letterpress printing ink composition consisting essentially of:a. Carbon black in the form of carbon black pellets pellets 115: 17.0% b. tall oil fatty acid: 64.4% c. Gilsonite tall oil blend: 18.6%.
 5. A letterpress printing ink composition consisting essentially of:a. Carbon black pigment in the range 6 to 19.8% b. Tall oil fatty acid and Gilsonite in the proportional range 70/30 to 80/20. 